Where does implementation lie? Assessing the determinants of delegation and discretion in post-Maastricht European Union

Drawing on a principal–agent framework the article analyses the European Union (EU) politics of delegation in the post-Maastricht era. By means of statistical analysis, it tests the impact of several variables upon the selection of national and supranational agents, as well as on the discretion they enjoy, on the basis of a recently collected data set of EU laws. Findings reveal that pooling and policy complexity favour the involvement of supranational actors in the implementation of EU laws. Moreover, the degree of supranational integration of a policy affects the likelihood of choosing supranational implementers. On the one hand, the Commission enjoys higher discretion vis-à-vis national actors when qualified majority voting applies, and when higher levels of conflict in the Council of Ministers is present. On the other, conflict between the European Parliament and the Council under codecision seems associated with lower supranational discretion, although the result needs further corroboration.